Stacked plate heat exchanger

ABSTRACT

A plate heat exchanger comprising a plurality of plates ( 12,13 ) which are stacked against each other and which are of a first and second type in order to form flow channels for a first and second medium. The plates form a heat exchanger block ( 2 ) with an upper side and a lower side and with two opposite side surfaces ( 10 ) and front faces ( 9 ). The first flow channels are peripherally sealed for the first medium and are fluidically connected to distributor and collector channels which are arranged in a vertical position with respect to the plate plane and which lead into inlet and outlet connection pieces ( 6,7 ) which are respectively arranged on the upper side and/or lower side ( 3,11 ). The second flow channels are open at the front surfaces ( 9 ) thereof and are sealed at the side surfaces ( 10 ) thereof. The open sides ( 9 ) form an inlet and outlet plane for the second medium.

The invention relates to a stacked plate heat exchanger in accordancewith the preamble of patent claim 1.

Stacked plate heat exchangers have been disclosed by DE-A 43 14 808 andDE-C 195 11 991 in the name of the present Applicant. This stackeddesign is cost-effective for heat exchangers in that a high number ofidentical parts of relatively simple configuration are used. Accordingto DE-A 43 14 808, the heat exchanger can be produced using a singletype of plate, which is in each case rotated through 180° duringassembly and stacking. In the case of DE-C 195 11 991, one embodimentuses two different types of plates in order to achieve different passageheights. This is advantageous in particular if the heat exchanger hasone liquid and one gaseous medium flowing through it, for examplecoolant and charge air in an internal combustion engine. In this stackedplate heat exchanger, the connection pieces for the charge air and thecoolant are either all arranged on one side, for example on the topside, or are arranged on two sides, i.e. the top side and the undersideof the heat exchanger. The inlet and outlet connection pieces aregenerally aligned with distribution and collection passages within theheat exchanger block, and the heat-transfer media flow transversely withrespect to the distribution and collection passages through flowpassages between the stacked plates or heat exchanger plates. Thisresults in a double 90° diversion for both media, which causes thepressure drop in the heat exchanger to increase. A pressure drop of thisnature is undesirable in particular for the routing of the charge air.

Therefore, it is an object of the present invention to improve a stackedheat exchanger of the type described in the introduction in such a waythat the pressure drop is reduced at least for one medium.

This object is achieved by the features of patent claim 1. According tothe invention, one medium, i.e. for example the charge air or theexhaust gas, is no longer diverted through 90°, but rather the gaseousmedium flows through the heat exchanger directly in the longitudinaldirection. This is achieved, in a modification to the standard stackedarrangement, by the plates which are stacked on top of one another onlybeing closed off at two opposite sides, but being open at the two endsides. The plates for the other medium, i.e. for example the coolant, onthe other hand, are closed at the periphery—as has hitherto beencustomary—and connected to in each case a distribution passage and acollection passage. A further advantage is that the inexpensive stackeddesign can be maintained yet at the same time the pressure drop for agaseous medium is reduced.

Advantageous configurations of the invention will emerge from thesubclaims.

According to an advantageous refinement of the invention, inlet andoutlet boxes with inlet and outlet connection pieces are fitted onto theend faces of the heat exchanger block, with the connection piecesarranged aligned with one another. This results in a particularly lowpressure drop for the gaseous medium, e.g. charge air, exhaust gas. Ifthe installation conditions require, the inlet or outlet connectionpiece may also be connected to the inlet or outlet box at apredeterminable angle of up to 90°. The boxes may advantageously beformed from a bent metal plate and two end plates which project beyondthe end faces. This enables the all-metal design, for example comprisingsteel or aluminum, to be maintained for this heat exchanger, which cantherefore be soldered in full “in one go” in the soldering furnace.However, the inlet and outlet boxes may also be designed as independentstructural units and can be joined to the heat exchanger blockindependently of the soldering operation, in particular after thesoldering operation, for example by welding or adhesive bonding.

According to a further advantageous configuration of the invention, theflow passages for the first medium, e.g. the coolant, are closed at theperiphery, specifically by a surrounding edge with a surrounding foldwhich is soldered to an adjacent plate. Consequently, the flow ofcoolant is hermetically sealed off from the second medium, for examplewith respect to the charge air or exhaust gas. The flow passages for thesecond medium are directly adjacent to the flow passages for thecoolant, but the charge air flow passages are largely open at the twoend sides of the heat exchanger block. To increase the heat transfercapacity, metal turbulence plates, which are soldered to the adjacentplates and therefore increase the strength of the heat exchanger block,may be arranged in the flow passages for the charge air or exhaust gas.Metal turbulence plates may also be arranged in a similar way in theflow passages for the coolant.

According to an advantageous refinement of the invention, thedistribution and collection passages for the coolant are formed bycup-like stamped formations in both plates. The stamped formations bearagainst one another and are soldered together in the region of theircontact surfaces, resulting in continuous passages for the coolant.Alternatives, such as intermediate rings or sleeves or passage sectionsfitted into one another, are also possible.

In another embodiment, the cup-like stamped formations are formedoutside the heat exchanger block, allowing better routing of the secondmedium within the heat exchanger block.

In an advantageous configuration of the invention, the flow passages forthe charge air are formed by a special type of plate, which has lateralflanged edges. These flanged edges are angled either once to form an Lsection or twice to form a C section and thereby form bearing surfaceswith the respectively adjacent plates. The plates are soldered to oneanother in the region of these bearing or contact surfaces and therebyform the flow passages for the charge air which are closed off withrespect to the outside, i.e. also form the lateral terminating walls ofthe heat exchanger block.

Exemplary embodiments of the invention are illustrated in the drawingsand described in more detail in the text which follows. In the drawings:

FIG. 1 shows a charge air/coolant cooler,

FIG. 2 shows the charge air/coolant cooler shown in FIG. 1 without theair boxes,

FIG. 3 shows a perspective illustration of the heat exchanger block ofthe charge air/coolant cooler shown in FIG. 1 and FIG. 2,

FIG. 4 shows a front view of the heat exchanger block shown in FIG. 3,

FIG. 5, 5 a, b, c show various views of a first type of plate (coolantplate),

FIG. 6, 6 a, 6 b show various views of a second type of plate (chargeair plate),

FIG. 7 shows an excerpt from a first modification of the heat exchangerblock,

FIG. 8 shows an excerpt from a second modification of the heat exchangerblock,

FIG. 9 shows an excerpt from a third modification of the heat exchangerblock,

FIG. 10 shows an excerpt from a fourth modification of the heatexchanger block, and

FIG. 11 shows an excerpt from a fifth modification of the heat exchangerblock.

FIG. 1 shows a stacked charge air/coolant cooler 1 for an internalcombustion engine of a motor vehicle having a coolant and charge aircircuit (not shown). The core of the charge air/coolant cooler 1 is aheat exchanger block 2, which is closed off at the top by a terminationplate 3 and at the end sides by air boxes 4, 5. The heat exchanger block2 on the one hand has coolant flowing through it, this coolant enteringthrough a coolant inlet connection piece 6 arranged on the top side 3and emerging again through a coolant connection piece 7 likewisearranged on the top side 3. The charge air (which has been heated by acompressor that is not shown) enters the charge air/coolant cooler 1 viaan inlet connection piece 8 arranged centrally on the air box 4 andleaves the charge air/coolant cooler 1, after having been cooled,through an outlet connection piece, which is not visible but is arrangedaligned with the inlet connection piece 8 at the outlet box 5.

FIG. 2 shows the charge air/coolant cooler 1 without the air boxes 4 and5 in accordance with FIG. 1. The heat exchanger block 2 has an open endface 9 and a closed side face 10 and is covered at the top by thetermination plate 3 and at the bottom by a termination plate 11. Aregion 3 a of the upper plate 3 and a region 11 a of the lower plate 11project beyond the end face 9. These two regions 3 a, 11 a thereforeform the side faces of the air box 4 (FIG. 1), which has been bent froma metal sheet. The plates 3, 11 project in a similar way beyond the rearend face (not visible) of the heat exchanger block 2, specifically bymeans of regions 3 b, 11 b. The air box 5 (FIG. 1) is therefore ofsimilar design to the air box 4.

FIG. 3 shows a perspective illustration of the heat exchanger block 2,which is constructed from two different types of plates stacked on topof one another, together with turbulence inlays. The first type of plateis what is known as a coolant plate 12, and the second type of plate iswhat is known as a charge air plate 13. The coolant plate 12 has twocircular openings 15, 16 (both plates are described in more detail inconnection with FIG. 5 and FIG. 6). Metal turbulence plates 14 for thecharge air, which enters the heat exchanger block 2 via the open endside 9, are arranged between the two plates 12, 13. The heat exchangerblock 2 has a closed side face 10, which is formed by flanged edges 13 aof the charge air plates 13. The opposite side face (not visible in thisillustration) is of similar design.

FIG. 4 shows a front view of the heat exchanger block 2, i.e. a viewonto the end face 9 and in the direction of flow of the charge air. Theheat exchanger block 2 is therefore constructed from the coolant plates12 and the charge air plates 13, which are stacked alternately on top ofone another. The coolant plate 12 has a well-like recess 17, from whichtwo cup-like elevations 18, 19, with the openings 15, 16 in the interior(cf. FIG. 3), are stamped. As seen in the drawing, the coolant plate 12is closed off at the top by a planar, surrounding fold 12 a. The chargeair plate 13 bears against this fold 12 a and therefore forms asurrounding contact surface with the fold 12 a in order for the twoplates 12, 13 to be soldered together in this region. The charge airplate 13 in each case extends laterally beyond the fold 12 a, where ithas flanged edges 13 a in the form of a C section on both sides. Theupper and lower (horizontal in the plane of the drawing) limbs of the Csection in each case form contact surfaces with the lower and upperlimbs, respectively, of the adjacent C sections, in order for them to besoldered together. Corresponding, oppositely directed stamped formations20, 21 are arranged at the charge air plates 13 aligned with thecup-shaped stamped formations 18, 19 of the coolant plates 12, so thatwhen the plates 12, 13 are stacked stamped formations 18, 20 and 19, 21in each case come to bear against one another, thereby forming adistribution passage 22, which extends continuously from the topdownward, and a collection passage 23 for the coolant. Coolant inlet andcoolant outlet are denoted by arrows bearing the designations KME andKMA. The flow passages for the coolant therefore correspond to thewell-like recesses 17, in which metal turbulence plates (not shown) arealso arranged. Turbulence inlays 14 are arranged between in each caseone coolant plate 12, i.e. the air side thereof, and an adjacent chargeair plate 13, these turbulence inlays thereby forming part of the flowpassages 24 for the charge air. As has already been mentioned, thecharge air enters the heat exchanger block 2 perpendicular to the planeof the drawing and flows through it in a straight direction, apart fromthe diversions caused by the cup-like stamped formations 18 to 21.

FIG. 5, 5 a to 5 c show various views of the coolant plate 12. FIGS. 5,5 a and 5 b show the rectangular plate 12, which is rounded at thecorners and has two openings 15, 16 that are arranged diagonallyopposite one another and are stamped out of the plate. The plate 12 isdeep-drawn and includes the recess 17 (cf. FIG. 5 c), the upper edge ofwhich merges into the encircling fold 12 a. In the region of theopenings 15 and 16, the recess 17 is adjoined by the cup-like stampedformations 18, 19. Although the illustration only shows rectangularplates 12, it is, however, also conceivable to use other geometricshapes, in particular if the cup-like stamped formations are arrangedoutside the main direction of flow.

FIG. 6, FIG. 6 a and FIG. 6 b show various views of the charge air plate13, once again using the same reference numerals as above. The basiccontour (FIG. 6 a) of the charge air plate 13 corresponds to that of thecoolant plate 12, except that the charge air plate 13 is slightly widerin the direction of the flanged edges 13 a. The charge air plate 13 hasa planar part 13 b, the size of which is at least sufficient for it tocover the fold 12 a of the coolant plate 12. The flanged edges 13 a forma C section with a vertical surface 13 a and a horizontal surface 13 c.In the stacked arrangement shown in FIG. 4, the latter bears against theunderside 13 b of the adjacent charge air plate 13. The two cup-likestamped formations 20, 21 with stamped-out openings 25, 26 are formedout of the planar part 13 b of the charge air plate 13, and the positionof these stamped formations and openings corresponds to the stampedformations 18, 19 and openings 15, 16 of the coolant plate 12.

FIG. 7 shows an excerpt from a modified embodiment of a heat exchangerblock 27 with modified charge air plates 28. The latter have a flangededge or vertically positioned rim 28 a the height h of which is suchthat an overlap a with the adjacent charge air plate 28 is produced,thereby creating a contact surface for the soldering.

FIG. 8 shows an enlarged excerpt from the heat exchanger block 2 fromFIG. 4 with the charge air plate 13 and the double flanged edge 13 a, 13c forming a C section. This charge air plate 13 is illustrated as anindividual part in FIG. 6. The present figure shows how the upper limb13 c of the C section bears against the underside of the planar part 13b of the charge air plate 13 and thereby forms a soldering surface.

FIG. 9 shows a further modification of a heat exchanger block 29 havinga charge air plate 30 and a modified coolant plate 31, the fold 32 ofwhich is extended toward the outside. The charge air plate 31—as alsoillustrated in FIG. 6—has a C-shaped edge section 30 a, 30 c, so thatthe extended fold 32 comes to bear against the limb 30 c of the Csection, thereby forming a soldering surface. The planar part 30 b ofthe charge air plate 30 bears against the fold 32.

FIG. 10 shows a further modification of a heat exchanger block 33 with amodified coolant plate 34 and a charge air plate 35 with a verticalangled section 35 a. The coolant plate 34 has an outwardly extendedflange part 36 which is angled off downward to form a vertical flangededge surface 36 a. The two surfaces 35 a of the charge air plate 35 and36 a of the coolant plate 34 bear against one another and thereby form asoldering surface for forming a closed flow passage for the charge air.

FIG. 11 shows a further modification of a heat exchanger block 37 with amodified coolant plate 38 and a charge air plate 39 which once again hasa C-shaped flanged edge section 39 a, 39 c. The coolant plate 38 has asurrounding fold 40, which is adjoined by a strip 40 a that is offsetdownward via a shoulder. This strip 40 a bears against the underside ofthe limb 39 c of the C section of the charge air plate 39 and therebyforms a soldering surface. The planar part 39 b of the charge air plate39 bears against the top side of the limb 39 c, so that in this regionthree wall thicknesses are positioned above one another.

1. A stacked plate heat exchanger, comprising a multiplicity of platesof a first type and a second type stacked on top of one another so as toform first flow passages for a first medium and second flow passages fora second medium, wherein pairs formed by one first type and one adjacentsecond type of plates define between them said first flow passage, andadjacent pairs of plates form between the adjacent pairs said secondflow passages, the stack of plates forming a heat exchanger block havinga top side and an underside and having in each case two opposite sidefaces and opposite end faces, wherein the first flow passages for thefirst medium are closed at their peripheral sides and are in fluidcommunication with distribution and collection passages, which arearranged perpendicular to the plane of the plates and respectively openout into inlet and outlet connection pieces arranged on the top sideand/or underside of the heat exchanger block, wherein the second flowpassages are designed to be largely open at the end faces such that theopen sides form an inlet plane and an outlet plane for the secondmedium, and wherein the second type of plates have lateral flanged edgeswhich are bent at a right angle with respect to the plane of the secondtype plate in a direction away from its respectively paired first typeplate and toward the adjacent pair of plates, and in the bent portion ofthe lateral flanged edge contains a solder surface adapted to besoldered to at least one of the first type or second type plate of theadjacent pair of plates, to close off the second flow passages at theside faces with respect to the outside and form the side faces of theheat exchanger block.
 2. The plate heat exchanger as claimed in claim 1,further comprising an inlet box and an outlet box for the second mediumconnected to the end faces.
 3. The plate heat exchanger as claimed inclaim 2, wherein the inlet and outlet boxes are each designed asindependent structural units joined to the heat exchanger block.
 4. Theplate heat exchanger as claimed in claim 2, wherein the inlet and outletboxes have inlet and outlet connection pieces that aligned with oneanother.
 5. The plate heat exchanger as claimed in claim 2, wherein atthe inlet and outlet boxes the inlet and outlet connection pieces arearranged at a predeterminable angle of up to 90° with respect to themain direction of flow.
 6. The plate heat exchanger as claimed in claim1, wherein the inlet and/or outlet boxes are formed by bent sheet-metalstrips and cover plates which protrude beyond the end faces.
 7. Theplate heat exchanger as claimed in claim 1, wherein the first type ofplate has a recess with a surrounding flat fold in the second type ofplate has a planar region (13 b) covering the fold, and each pair of thefirst and second types of plates are joined to one another in the regionof the fold and between them enclose the first flow passage for thefirst medium.
 8. The plate heat exchanger as claimed in claim 1, whereinthe distribution and collection passages are formed by passage sectionswhich are arranged between the respective plates of each pair of platesand connect the plates of each pair together.
 9. The plate heatexchanger as claimed in claim 1, wherein the passage sections aredesigned as cup-like elevations and are shaped out of the plates. 10.The plate heat exchanger as claimed in claim 9, wherein the cup-likeelevations are arranged outside the main direction of flow.
 11. Theplate heat exchanger as claimed in claim 1, further comprising metalturbulence plates arranged in the first and/or second flow passages. 12.The plate heat exchanger as claimed in claim 1, wherein the flangededges form an overlap with the flanged edge of the second type of platein the adjacent pair of plates.
 13. The plate heat exchanger as claimedin claim 1, wherein the flanged edges are angled twice and form a Csection which bears against a second type of plate in the adjacent pairof plates.
 14. The plate heat exchanger as claimed in claim 1, whereinthe flanged edges form a C section which bears against the first type ofplate in the adjacent pair of plates.
 15. The plate heat exchanger asclaimed in claim 1, wherein the first type of plates have lateralflanged edges, and the flanged edges of the first and second types ofplates are oppositely directed and are arranged so as to bear againstone another.
 16. The plate heat exchanger as claimed in claim 1, whereinthe flanged edge is angled twice and forms a C section with a free limbwhich on one side bears against the first type of plate and on the otherside bears against the second type of plate in the adjacent pair ofplates.
 17. A charge air/coolant cooler having the plate heat exchangeras claimed in claim
 1. 18. An exhaust gas/coolant cooler having theplate heat exchanger as claimed in claim
 1. 19. A stacked plate heatexchanger as claimed in claim 1, wherein the side faces are generallyplanar.